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Glen.Canyon.Dam
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Glen Canyon Dam Suckered Us
Man-Made Flood Rushes Through Grand Canyon
PAGE, Ariz. — Two giant steel tubes began shooting water from the base of the Glen Canyon Dam Wednesday as the federal government started a manmade flood of the Grand Canyon. |
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They hope the three-day flood will restore the canyon's ecosystem, which was permanently changed after the construction of the Glen Canyon Dam in 1963.
The Colorado River downstream used to be warm and muddy, but now it's cold and clear.
The shift helped speed the extinction of four fish species and push two others, including the endangered humpback chub, near the edge.
Officials hope the flooding will stir up sediment and redistribute it through the canyon, which will get about four to five times the normal amount of water released from the dam during this week's flood.
In 1996, the government staged the first artificial flood in the canyon, opening Glen Canyon Dam's bypass tubes for several days in an attempt to replicate natural cycles. A second test in 2004 taught scientists the importance of sand and sediment.
The dam traps almost all the sediment that once flowed down the river, which is why beaches and habitats have eroded. A good monsoon season can wash significant quantities of sand down the Paria and Little Colorado rivers, which empty into the big Colorado below the dam.
The flood will scour and reshape miles of sandy banks on the floor of the Grand Canyon. Flows in the Grand Canyon would increase to 41,000 cubic feet per second for nearly three days — four to five times the normal amount of water released from the Glen Canyon Dam.
What scientists and environmentalists want to see is what will happen to the fish and the canyon when the gates close at dam and the staged flood recedes.
Federal officials insist they have progressed with long-term plans to offset the effects of the dam on the river and the Grand Canyon. The chub, the fish at the center of much of the dispute, has recovered some of its lost numbers since the last flood. Scientists also think they better understand when to trigger future floods.
"Our ultimate purpose is to learn whether or not this is a viable strategy for creating sandbars and habitats for native fish," said John Hamill, chief of the Grand Canyon Monitoring and Research Center, part of the U.S. Geological Survey.
Environmental groups argue that the upcoming flood again delays long-term changes to the river's management, further jeopardizing the canyon's health.
They want federal officials to permanently alter the dam's operation instead of repeating the same test, adopting a seasonally adjusted plan that better mimics nature.
Nikolai Lash, senior program director for the Grand Canyon Trust, a group that has long fought the government over its management of the dam, said the March flood was hastily planned after the trust sued the government last year for failing to protect the river.
He said the experiment was purposely designed as a single test, even though most scientists think floods must occur regularly.
"They're trying to make it appear that they're doing something beneficial when they're just doing it for appearances," he said. "It's being manipulated to be a 'one and done,' even though we know that doesn't work."
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